With the Duke and Duchess of Cambridge expecting a baby in July, British lawmakers are rushing to bring the laws governing royal succession into the 21st century. The current rules, Deputy Prime Minister Nick Clegg said Monday, are from a “bygone age” and sent the wrong message about modern Britain, reports the Daily Mail.

Currently, if the Duchess of Cambridge gives birth to a baby girl, then that child would lose her place in the line of succession to the throne if Kate subsequently gave birth to a son.

Additionally, current rules prevent a future monarch from marrying a Catholic — part of anti-Catholic laws that once also banned them from voting, attending university or teaching — and date back to the Act of Settlement law of 1701.

Under the new proposals, a first-born girl of the Duke of Cambridge will inherit the throne regardless of whether she gains any younger brothers in the future, and royal heirs will have the right to marry Catholics.

On the surface, changing the rules seems uncontroversial. But traditionalists have complained, reports the Mail, that the changes haven’t been properly thought through and could open a Pandora’s Box of constitutional issues. Prince Charles himself has expressed concern about what will happen if his grandchild is allowed to marry a Roman Catholic, citing “potential consequences for the delicate relationship between the state and the Church of England,” as the Daily Mailput it earlier this month.

“With monarchy, you should agree the rules and stick to them,” writes Charles Moore in the Daily Telegraph. “Not for nothing is the original act of 1701 called the Act of Settlement. It doesn’t much matter what the rules are – elective, first-born, male line only, religious choice, lottery – but they must be settled.”

Much of the concern stems from how quickly the new legislation is being rushed through parliament — with only two days of discussion by MPs. “The first child of the Duke and Duchess will be heir presumptive regardless of its sex. Only if that child is female and a further child male would the existing law have any bearing – so why the hurry?” asked the Telegraph Monday.